During electricity generation in power plants, wherein electricity generated is fed into a current network, attention must be paid to the in-phase infeed of electricity. In thermal power plants, in which electricity is generated by turbine-driven generators, the turbine must thus be brought to an appropriate angular position in relation to the phase of the current network, in order to permit the infeed of electricity. To be precise, this naturally corresponds to the angular position of the generator rotor. As the generator rotor, as a rule, is rigidly connected to the turbine rotor, turbine synchronization is consistently referred to herein whereas, in practice, this term actually applies to the generator.
According to the prior art, it is customary for the turbine to be brought up to network frequency, independently of the phase angle of the current network. The turbine is thus brought to the correct phase angle using a “synchronizing device”. To this end, the turbine is slightly accelerated or decelerated, in casual terms “run-up” or “run-down”, until such time as the appropriate phase angle is achieved.